In recent years, attempts have been made to execute various operations (hereinafter referred to as “task(s)”) such as a porter's service, a receptionist's service, and a guide service, using an autonomous mobile robot (hereinafter just referred to as “mobile robot(s)”), and these attempts have been come into practical use in various fields.
For example, Japanese Laid-open Patent Application No. 2001-92529 discloses a battery charge controlling system for mobile robots which carry and deliver burdens or baggage in a manufacturing factory where FA (factory automation) is introduced.
In this battery charge controlling system, a host computer controls traffic of the mobile robots, so that each mobile robot is controlled under instructions from the host computer and operates to carry and deliver burdens or baggage or to move to a battery charge station.
These mobile robots perform a porter's service in a factory where the environment such as temperature and humidity are kept constant, and their traveling passages or targeting locations are determined in advance. Therefore, the amount of battery expense to be consumed by the mobile robot (battery consumption) may be more or less in the range of prediction, so that the mobile robot hardly stops during its travel for carrying and delivering burdens or baggage due to the lack of battery charge.
Meanwhile, in the mobile robots performing tasks such as a receptionist's service and a guide service under the environment where human exists, there may be a necessity for a frequent response to human interaction (human interaction response) during the execution of the tasks because of the existence of human.
For instance, if a human exists or baggage is placed on a traveling passage along which a mobile robot moves, it is necessary for the mobile robot to execute a response (human interaction response) for changing the traveling passage to keep away from the human or baggage.
Further, when the mobile robot is under execution of a task such as passing baggage to a particular person (baggage delivering task), the person to whom the mobile robot has to pass the baggage (i.e., target person) may not always stay in the same location. In this case, the mobile robot has to continue the human interaction response until the mobile robot reaches the target person.
In this manner, if the mobile robot executes a human interaction response during the execution of task, the amount of battery expense required for this human interaction response is added further to the amount of battery expense required for the execution of the task. This amount of battery expense for the human interaction response is much different depending on the human interaction response to be executed. It is therefore difficult to predict the amount of battery expense (battery consumption) to be consumed by the mobile robot during the execution of the task.
As described above, because of this unexpected factor as the human interaction response, it is impossible to generally predict the battery consumption when a mobile robot performs the task. Therefore, in the case of the mobile robots performing tasks under the environment where human exists, compared with the mobile robots traveling in a factory, it is more liable to occur disadvantages that the task cannot be executed or all the tasks assigned to the mobile robot cannot be executed due to lack of the battery in the halfway of the task.
In view of this, there is a demand for an apparatus which controls a plurality of mobile robots to effectively perform a plurality of tasks even in the condition where an unexpected factor such as human interaction response exists. Namely, there is a strong need to provide a robot control apparatus which allows a plurality of mobile robots to effectively perform a plurality of tasks based on the remaining amount of charge in the battery of each mobile robot as a power source of the robot, by reevaluating the execution order of the tasks assigned to each robot, rearranging unexecuted tasks to other mobile robots, and reassigning the unexecutable task (task determined to be difficult for execution) to another mobile robot.